PROLEGOMENA 3 



My predecessors in this work have been few in number. The volumes 

 of Haller's, Buffon's, and Milne-Edwards' great treatises, in which 

 they deal with the phenomena of generation, contain as much in- 

 formation as was available up to 1863, but this is purely of historical 

 interest to us. In 1885, W. Preyer, Professor of Physiology at Jena, 

 published his Spezielle Physiologie des Embryo, which still remains a most 

 valuable review, and indeed, even to-day, is the only existing book 

 specially devoted to embryonic physiology. The present century 

 has produced only three books which even touch upon my subject, 

 namely, T. B. Robertson's Chemical Basis of Growth and Senescence, 

 F. H. A. Marshall's Physiology of Reproduction and E. Faure-Fremiet's 

 La Cinetique du Developpement. The first of these was admittedly written 

 to support a particular theory, and in any case says comparatively 

 little about physico-chemical embryology. The second and the third 

 deal with it only as a constituent part of a much wider field. In 

 Marshall's case, the whole array of facts relating to oestrus and 

 breeding, fertilisation and fertility, lactation and sex determination, 

 have to be dealt with, and only three chapters out of sixteen are 

 devoted to the subject of this book. The first of these is contributed 

 by W. Cramer, and covers the biochemistry of the sexual organs, in- 

 cluding the unfertiUsed egg ; the second, which deals with foetal 

 nutrition and the placenta, is by J. Lochhead ; and the third, by these 

 two investigators together, is concerned with changes in the maternal 

 organism during pregnancy. Admirable as these chapters are, they 

 are now rather out of date. Moreover, though one or two corners 

 of the field I have before me were covered in Marshall's book, it was 

 from a quite different standpoint. 



Faure-Fremiet's work is exactly analogous; it deals with physico- 

 chemical embryology only, as it were, in passing. The relevant dis- 

 cussion takes up only two chapters out of seven ; the rest are occupied 

 with tissue culture, growth of protozoal populations, and general 

 cytology. His book covers, it might be said, the third and fourth 

 corners : all the main expanse of the field remains. 



Thus neither of these books deals with physico-chemical embryo- 

 logy in an exhaustive and comprehensive fashion, treating it as, in 

 my view, it ought to be treated, with the thoroughness which is 

 deserved by a new branch of natural knowledge. Inseparable, how- 

 ever, from thoroughness of treatment is the submergence of the parts 

 of more general interest under a mass of detail, and it may be well. 



